[GitHub] stale[bot] closed pull request #1964: [AIRFLOW-722] Add Celery queue sensor

[GitBox <gi...@apache.org>]

stale[bot] closed pull request #1964: [AIRFLOW-722] Add Celery queue sensor
URL: https://github.com/apache/airflow/pull/1964
 
 
   

This is a PR merged from a forked repository.
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diff --git a/airflow/contrib/sensors/celery_queue_sensor.py b/airflow/contrib/sensors/celery_queue_sensor.py
new file mode 100644
index 0000000000..3cb7d5dc5a
--- /dev/null
+++ b/airflow/contrib/sensors/celery_queue_sensor.py
@@ -0,0 +1,87 @@
+# -*- coding: utf-8 -*-
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+
+from airflow.operators.sensors import BaseSensorOperator
+from airflow.utils import apply_defaults
+from celery.task.control import inspect
+
+
+class CeleryQueueSensor(BaseSensorOperator):
+    """
+    Waits for a Celery queue to be empty. By default, in order to be considered 
+    empty, the queue must not have any tasks in the ``reserved``, ``scheduled`` 
+    or ``active`` states.
+
+    :param celery_queue: The name of the Celery queue to wait for.
+    :type celery_queue: str
+    """
+    @apply_defaults
+    def __init__(
+            self,
+            celery_queue,
+            af_task_id=None,
+            *args,
+            **kwargs):
+        """The constructor."""
+        super(CeleryQueueSensor, self).__init__(*args, **kwargs)
+        self.celery_queue = celery_queue
+        self.af_task_id = af_task_id
+
+    def _check_task_id(self, context):
+        """
+        Gets the returned Celery result from the Airflow task
+        ID provided to the sensor, and returns True if the
+        celery result has been finished execution.
+
+        :param context: Airflow's execution context
+        :type context: dict
+        :return: True if task has been executed, otherwise False
+        :rtype: bool
+        """
+        ti = context['ti']
+        celery_result = ti.xcom_pull(task_ids=self.af_task_id)
+        return celery_result.ready()
+
+    def poke(self, context):
+        """Poke."""
+        from celery.task.control import inspect
+
+        if self.af_task_id:
+            return self._check_task_id(context)
+
+        i = inspect()
+        reserved = i.reserved()
+        scheduled = i.scheduled()
+        active = i.active()
+
+        try:
+            reserved = len(reserved[self.celery_queue])
+            scheduled = len(scheduled[self.celery_queue])
+            active = len(active[self.celery_queue])
+
+            logging.info(
+                'Checking if celery queue {0} is empty.'.format(
+                    self.celery_queue
+                )
+            )
+
+            return reserved == 0 and scheduled == 0 and active == 0
+        except KeyError:
+            raise KeyError(
+                'Could not locate Celery queue {0}'.format(
+                    self.celery_queue
+                )
+            )


 

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